Alarm Circuits
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The alarm may be used for a variety of applications, such as frost monitor, room temperature monitor, and so on. In the quiescent state, the circuit draws a current of only a few microamperes, so that, in theory at least, a 9 V dry battery (PP3, 6AM6,.... -
This circuit can be built from readily available low-cost components, some of which may even be hiding in your junkbox! The indicated value of 22 for resistor R1 causes an average current of about 65 mA through infrared emitter D1. Because the IRED is.... -
This circuit features automatic exit and entry delays - an optional instant alarm zone - an optional intermittent siren output - and an automatic reset. By adding external relays you can immobilize the vehicle and flash the lights. The alarm is set by.... -
In this article we will be discussing about a home security alarm circuit. This is a LPG gas leakage sensor circuit that detects the outflow of LPG gas and alerts the user via audio and visual indications. The heart of this simple engineering project is a.... -
This is a simple 12V rechargeable smart battery charger circuit. You can use this best battery charger circuit as car battery chargers, Inverter battery charger, Emergency light battery charger etc. An automatic indicator alarm circuit also comes along with.... -
Water tank overflow liquid level sensor alarm circuit is a simple electronics project for school students. In the previous articles we had discussed about numeric water level indicator and water level controller circuit, but those circuits are much complex.... -
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Have you ever thought aboutimplementing your own home security alarm systems It`s one of the simplest and interesting circuits for electronic beginners. Our new home security equipment uses aLDR (Light Depended Resistor) to detect security problems. Theft.... -
Many fire alarm circuits are presented here, but this time a new circuit using a thermistor and a timer to do the trick. The circuit is as simple and straight forward so that, it can be easily implemented. The thermistor offers a low resistance at high.... -
The automatic door handle alarm circuit gives a audible alarm and glows a LED when somebody touches the handle of the door. The circuit is latching type and continues to produce sound until it is switched off. The transistor Q1 is wired as an astable.... -
Here is a simple fire alarm circuit based on a Light Dependent Resistor (LDR) and lamp pair for sensing the fire. The alarm works by sensing the smoke produced during fire. The circuit produces an audible alarm when the fire breaks out with smoke. When there.... -
Fridge Door Alarm circuit or a Refrigerator door open alarm using 555 Timer IC, which produces an audible alarm if the door left open for a preset time.... -
The high and low voltage cut-off with delay and alarm circuit with circuit diagram is explained in this post.... -
Infrared (IR) Motion Detector Circuit with motion detector alarm and infrared sensor.The motion sensor circuit diagram and working is given in detail.... -
The rain alarm circuit working is explained in detail. The rain alarm project is explained with circuit diagram.... -
A timer circuit using IC 4060 is given here. The IC 4060 is a 14 stage binary counter with a built-in oscillator. R2, R7, C1 are the components that determine the frequency of the oscillator and the outputs will become high one after other and only one at a.... -
Here is a simple shock sensitive alarm circuit that has many many applications fro home to automobiles. The main application of this circuit is to use it as an anti theft alarm in automobiles. A peizo electric sensor is used as the shock sensor which has to.... -
A simple burglar alarm circuit diagram and schematic. This can be used as anti theft alarm by attaching the burglar alarm circuit to window foil.... -
Here is the circuit diagram of an ultra sensitive intruder alarm. The shadow of an intruder passing few meters nearby the circuit is enough to trigger the alarm. Here IC2 uA 741 is wired as a sensitive comparator, whose set point is set by R6 &R7. The.... -
High Power Siren Circuit This article is all about a comparatively strong siren circuit useful for any purpose. A complementary transistor pair (BC 557 & 337) is arranged as an oscillator, directly drives the speaker. Transistor Q1(BC 557) is used to provide.... -
This is a simple Water level alarm circuits made using 555 Timer IC. Circuit will produce an alarm when the water level reaches a preset level.... -
This is just a fun/hobby circuit which can be used as a water sensor circuit or a liquid sensor circuit.What it does is sound an alarm in presence of water/liquid at its probes.... -
Here is the circuit diagram of a very simple wire loop alarm based on a N-channel enhancement FET 2N700, a buzzer and few passive components. In normal condition the gate of 2N700 (Q1) is connected to the ground through a 100K resistor (R2) and the wire.... -
This simple circuit will produce an alarm whenever the temperature falls below zero degree. A thermistor is used here to sense temperature. The op-amp LM7215 is used to compare the reference voltage and voltage from the thermistor network. Reference voltage.... -
This circuit suitable for a small office or home environment, it can also be adapted to use a combination lock or keypad to set and reset the .... -
This is a circuit of 6 Zone Alarm with LED Display . This alarm system has 6 independent zones, a 7 segment LED display, 1 timed entry/exit zone .... -
he following circuit shows a Photo Alarm Electronic Circuit. This circuit based on the 555 Timer IC. Features: LDR ( photoresistive cell), .... -
The following circuit shows about Alarm Power Supply Circuit Diagram. Features: 1-amp current, suitable for the Modular Burglar Alarm, 12-volts .... -
The following circuit shows about 9V Power Supply For Garage Shed Alarm Circuit Diagram. Features:single-zone burglar alarm circuit, used with the .... -
overhead detector (fire alarm) circuit is a precision integrated temperature sensor type LM35 (IC1), which provides an accurately linear and .... -
the function of this circuit for detects a sudden shadow falling on the light-sensor and sounds the bleeper when this happens. The light sensor is .... -
The following circuit shows about Fire alarm circuit diagram With NE555 IC. Features: works as the heat sensor, 10 kilo-ohms resistance of the .... -
The following circuit shows about Battery Powered Burglar Alarm Sensor Circuit. Features: foil tape and PIRs, such as magnetic-reed contacts, ....
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is.... -
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to.... -
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This.... -
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the.... -
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,.... -
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the.... -
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power.... -
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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